Complete the sentences.Use the correct from of the verbs in brackets.
1.If you______two books,you______one free.(Buy,get)
2.The menu______on the screen if you_______this button twice.(Appear,press)
3.If dogs_________chocolate,it______them ill.(Eat,make)
4.If water______,it_____(Freeze,expand)
5.If you______water to 100°C,it______.(Heat,boil)